As is understood, four motion feed mechanisms (also known as drop feed mechanisms) have been known for a number of years. With this particular type mechanism, movement of the feed dog is comprised of two components; namely, a height wise movement known as feed "lift" and a horizontal movement known as feed "advance". As is well known, the "advance" motion of the feed dogs determine the stitch length. In an industry such as sewing, where it is necessary to handle varying workpieces, it has been heretofore considered desirable to provide a sewing machine with a feed mechanism which is capable of accomplishing varying stitch lengths as well as develop a feed dog movement in a plurality of directions, e.g. forward and reverse feed relative to the machine needle.
Additionally, some of these machines are provided with means for adjusting the stitch length of the machine. In these machines, however, adjustment of the forward feed stitch length simultaneously and equally reflects adjustment of the stitch length in the reverse feed direction. That is, the art fails to show independent adjustment of the stitch lengths in either feed direction by using a single control knob.